Oral Nanoscience, Bristol Dental School, University of Bristol, Bristol, UK.
ACCIS, Queens School of Engineering, University of Bristol, Bristol, UK.
J Mater Sci Mater Med. 2020 Mar 11;31(3):33. doi: 10.1007/s10856-020-06370-0.
All chronic wounds are colonised by bacteria; for some, colonisation progresses to become infection. Alginate wound dressings are used for highly exuding chronic wounds as they are very absorbent, taking up large quantities of exudate while maintaining a moist wound bed to support healing. Some alginate dressings are doped with antimicrobials, most commonly silver, but evidence regarding the efficacy of these is largely inconclusive. This manuscript describes the development and in vitro assessment of alginate materials doped with chlorhexidine hexametaphosphate (CHX-HMP), a sparingly soluble salt which when exposed to aqueous environments provides sustained release of the common antiseptic chlorhexidine. Comparator materials were a commercial silver alginate dressing material and an alginate doped with chlorhexidine digluconate (CHXdg). CHX-HMP alginates provided a dose-dependent CHX release which was sustained for over 14 days, whereas CHXdg alginates released limited CHX and this ceased within 24 h. CHX-HMP and silver alginates were efficacious against 5 major wound pathogens (MRSA, E. coli, P. aeruginosa, K. pneumoniae, A. baumannii) in a total viable count (TVC) and an agar diffusion zone of inhibition (ZOI) model. At baseline the silver alginate was more effective than the CHX-HMP alginate in the TVC assay but the CHX-HMP alginate was the more effective in the ZOI assay. After 7 days' artificial aging the CHX-HMP alginate was more effective than the silver alginate for four of the five bacteria tested in both assays. These materials may ultimately find application in the development of wound dressings for chronic wounds that provide sustained antimicrobial protection.
所有慢性伤口都有细菌定植；对于某些伤口，定植会进展为感染。藻酸盐伤口敷料用于高度渗出的慢性伤口，因为它们非常吸液，可以吸收大量渗出物，同时保持湿润的伤口床以支持愈合。一些藻酸盐敷料中掺杂了抗生素，最常见的是银，但关于这些抗生素疗效的证据很大程度上尚无定论。本文描述了掺杂了氯己定六亚甲基膦酸盐（CHX-HMP）的藻酸盐材料的开发和体外评估，CHX-HMP 是一种难溶盐，当暴露于水相环境时，可提供持续释放常见防腐剂氯己定。比较材料是一种商业的银藻酸盐敷料材料和一种掺杂了氯己定葡萄糖酸盐（CHXdg）的藻酸盐。CHX-HMP 藻酸盐提供了剂量依赖性的 CHX 释放，可持续超过 14 天，而 CHXdg 藻酸盐释放有限的 CHX，在 24 小时内停止。CHX-HMP 和银藻酸盐在总活菌计数（TVC）和琼脂扩散抑菌区（ZOI）模型中对 5 种主要伤口病原体（MRSA、大肠杆菌、铜绿假单胞菌、肺炎克雷伯菌、鲍曼不动杆菌）有效。在基线时，银藻酸盐在 TVC 测定中比 CHX-HMP 藻酸盐更有效，但在 ZOI 测定中 CHX-HMP 藻酸盐更有效。经过 7 天的人工老化后，CHX-HMP 藻酸盐在两种测定中对测试的 5 种细菌中的 4 种都比银藻酸盐更有效。这些材料最终可能会应用于开发用于慢性伤口的伤口敷料，以提供持续的抗菌保护。
